Detecting the Higgs Bosons of Minimal Supergravity with Muon Pairs

The prospects at the CERN LHC are investigated for the discovery via decays into muon pairs of neutral Higgs bosons in the minimal supergravity model. Promising results are found for the CP-odd pseudoscalar ($A^0$) and the heavier CP-even scalar ($H^0$) Higgs bosons at large $\tan\beta \equiv v_2/v_1$. For \tan\beta \agt 10 and 100 GeV \alt m_A,m_H \alt 550 GeV, the $A^0$ and the $H^0$ masses could be precisely reconstructed from the dimuon invariant mass.Comment: 12 pages, REVTEX, 4 figure

Higgs Boson Discovery Potential of LHC in the Channel pp→γγ+jetpp \to\gamma\gamma+jet

We discuss the SM Higgs discovery potential of LHC in the reaction $pp\to H+ jet\to\gamma\gamma+jet$ when the jet is observed at sufficiently high $E_t$ to be reliably identified. We conclude that this channel gives promising discovery possibilities for the Higgs boson mass range 100-140 GeV, during LHC operation at a low luminosity. With 30 fb$^{-1}$ of accumulated data and for $M_H=120$ GeV about 100 signal events could be observed with the number of background events larger by a factor of 2 only, showing a signal significance $S/\sqrt{B}\sim 7$. We use the difference of distributions in the partonic subprocess energy $\sqrt{\hat s}$ for the signal and background for a better separation of the signal.Comment: 15 pages including 6 figures, LaTeX, use epsfig.sty. To appear in Phys.Lett.B. In this replacement minor LaTeX improvements are mad

Chiral restoration at finite temperature with meson loop corrections

We investigate chiral-restoration patterns of QCD for N_{c}=3 and N_{f}=2 at finite temperature (T) and zero quark-chemical potential beyond the chiral limit, indicating the explicit chiral-symmetry breaking. To this end, we employ the instanton-vacuum configuration for the flavor SU(2) sector and the Harrington-Shepard caloron for modifying relevant instanton parameters as functions of T. The meson-loop corrections (MLC), which correspond to 1/N_{c} corrections, are also taken into account to reproduce appropriate m_{q} dependences of chiral order parameters. We compute chiral condensate as a function of T and/or m_{q}. From the numerical calculations, we observe that MLC play an important role to have a correct universality-class behavior of chiral-restoration patterns in this framework, depending on m_{q}: Second-order phase transition in the chiral limit, m_{q}=0 and crossover for m_{q}>0. Without MLC, all the restoration patterns are crossover, due to simple saddle-point approximations. It turns out that T^{\chi}_{c}=159 MeV in the chiral limit and T^{\chi}_{c}=(177,186,196) MeV for m_{q}=(5,10,15) MeV, using the phenomenological choices for the instanton parameters at T=0.Comment: 12 pages, 6 figure

Discovering the Higgs Bosons of Minimal Supersymmetry with Tau Leptons and a Bottom Quark

We investigate the prospects for the discovery at the CERN Large Hadron Collider or at the Fermilab Tevatron of neutral Higgs bosons through the channel where the Higgs are produced together with a single bottom quark and the Higgs decays into a pair of tau leptons, $bg \to b\phi^0 \to b\tau^+\tau^-, \phi^0 = h^0, H^0, A^0$. We work within the framework of the minimal supersymmetric model. The dominant physics background from the production of $b\tau^+\tau^-$, $j\tau^+\tau^-$ ($j = g, u, d, s, c$), $b\bar{b}W^+W^-$, $W+2j$ and $Wbj$ is calculated with realistic acceptance cuts and efficiencies. Promising results are found for the CP-odd pseudoscalar ($A^0$) and the heavier CP-even scalar ($H^0$) Higgs bosons with masses up to one TeV.Comment: 14 pages, 7 figure

Astrophysical Constraints on Large Extra Dimensions

In the Kaluza-Klein (KK) scenario with n large extra dimensions where gravity propagates in the 4+n dimensional bulk of spacetime while gauge and matter fields are confined to a four dimensional subspace, the light graviton KK modes can be produced in the Sun, red giants and supernovae. We study the energy-loss rates through photon-photon annihilation, electron-positron annihilation, gravi-Compton-Primakoff scattering, gravi-bremsstrahlung and nucleon-nucleon bremsstrahlung, and derive lower limits to the string scale M_S. The most stringent lower limit obtained from SN1987A leads to $M_S> 30 - 130$ TeV (2.1-9.2 TeV) for the case of two (three) large extra dimensions.Comment: 12 pages, 4 figures, 2 tables; minor corrections, references adde

The Nucleon Spin Polarizability at Order O(p4{\cal O}(p^4) in Chiral Perturbation Theory

We calculate the forward spin-dependent photon-nucleon Compton amplitude as a function of photon energy at the next-to-leading (${\cal O}(p^4)$) order in chiral perturbation theory, from which we extract the contribution to nucleon spin polarizability. The result shows a large correction to the leading order contribution.Comment: 7 pages, latex, 2 figures included as .eps file

Phenomenology of a String-Inspired Supersymmetric Model with Inverted Scalar Mass Hierarchy

Supersymmetric (SUSY) models with heavy sfermions ($m_{\tilde{f}} \sim 10$ TeV) in the first two generations and the third generation sfermion masses below 1 TeV can solve the SUSY flavor and the CP problems as well as satisfy naturalness constraints. We study the phenomenology of a string-inspired scenario and compare it with the minimal supergravity unified model (mSUGRA). The SUSY trilepton signature at the upgraded Tevatron, the $b\to s\gamma$ branching fraction and the neutralino dark matter relic density in this model can differ significantly from the mSUGRA model.Comment: Version to appear in Physics Letters

The Chern-Simons Coefficient in Supersymmetric Non-abelian Chern-Simons Higgs Theories

By taking into account the effect of the would be Chern-Simons term, we calculate the quantum correction to the Chern-Simons coefficient in supersymmetric Chern-Simons Higgs theories with matter fields in the fundamental representation of SU(n). Because of supersymmetry, the corrections in the symmetric and Higgs phases are identical. In particular, the correction is vanishing for N=3 supersymmetric Chern-Simons Higgs theories. The result should be quite general, and have important implication for the more interesting case when the Higgs is in the adjoint representation.Comment: more references and explanation about rgularization dpendence are included, 13 pages, 1 figure, latex with revte